Phyllosomas of spiny lobsters, genus Jasus, Panuirus and Palinurus were cultured from egg stage to uerulus/postpueruus stage in the laboratory at Sanriku. These pueruli and those sampled by collectors in the sea were used for ecological and physiological observations.(1) Complete larval development was shown with Nannochloropsis sp. at 10^6 - 5 x 10^6/m1, Ammonium-N < 1.4 ppm, COD < 1.2 ppm and Bacterial number at 10^3 - 10^5 CFU/m1. Number of pueruli produced in 1992 and 1993 was 5, 24, 4 and 2 for J.edwardsii, J.verreauxi, Panulirus japonicus and Palinurus elephas, respectively. Pueruli of J.edwardsii were collected in North Island, New ZEALAND, J.verreauxi in New South Wales, Austraa and Panulirus argus in Florida, U.S.A..(2) The shortest duration of puerulus stage was 20 days for Jasus and 12 days for Panulirus. Pueruli molted into juvenile stage without feeding. Duration of the puerulus stage varied with water teperature. Pueruli were torelable to change of water teperature : Jasus to 28ﾟC at high water teperature range and Panulirus to 15ﾟC at low water teperature range. Preference for substrtum was seen in crevice n rocks for J.edwardsii, in algae for J.verreauxi and in both for P.japonicus. Puerui of P.elephas preferred on the top of rocks. Diurnal burrowing behaviur was observed for J.edwardsii(3) Pueruli were transparent just after metamorphosis. Hepatopancreas was visible after settlement and pigmentation occurred before mult Existence of fat body was observed in the haemocoel of the puerulus. The quantity of the fat bodies reduced with the progress of development. The fat body is considered as as a storage site of nutrition during the puerulus stage.